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f3bc08c5 MD |
1 | /* |
2 | * ring_buffer_mmap.c | |
3 | * | |
4 | * Copyright (C) 2002-2005 - Tom Zanussi <zanussi@us.ibm.com>, IBM Corp | |
5 | * Copyright (C) 1999-2005 - Karim Yaghmour <karim@opersys.com> | |
886d51a3 | 6 | * Copyright (C) 2008-2012 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
f3bc08c5 | 7 | * |
886d51a3 MD |
8 | * This program is free software; you can redistribute it and/or modify |
9 | * it under the terms of the GNU General Public License as published by | |
10 | * the Free Software Foundation; only version 2 of the License. | |
f3bc08c5 | 11 | * |
886d51a3 MD |
12 | * This program is distributed in the hope that it will be useful, |
13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | * GNU General Public License for more details. | |
16 | * | |
17 | * You should have received a copy of the GNU General Public License along | |
18 | * with this program; if not, write to the Free Software Foundation, Inc., | |
19 | * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. | |
20 | * | |
21 | * Re-using code from kernel/relay.c, hence the GPLv2 license for this | |
22 | * file. | |
f3bc08c5 MD |
23 | */ |
24 | ||
25 | #include <linux/module.h> | |
26 | #include <linux/mm.h> | |
27 | ||
c075712b MD |
28 | #include <wrapper/ringbuffer/backend.h> |
29 | #include <wrapper/ringbuffer/frontend.h> | |
30 | #include <wrapper/ringbuffer/vfs.h> | |
f3bc08c5 MD |
31 | |
32 | /* | |
33 | * fault() vm_op implementation for ring buffer file mapping. | |
34 | */ | |
52a391bd | 35 | static int lib_ring_buffer_fault_compat(struct vm_area_struct *vma, struct vm_fault *vmf) |
f3bc08c5 MD |
36 | { |
37 | struct lib_ring_buffer *buf = vma->vm_private_data; | |
38 | struct channel *chan = buf->backend.chan; | |
5a8fd222 | 39 | const struct lib_ring_buffer_config *config = &chan->backend.config; |
f3bc08c5 | 40 | pgoff_t pgoff = vmf->pgoff; |
0112cb7b | 41 | unsigned long *pfnp; |
f3bc08c5 MD |
42 | void **virt; |
43 | unsigned long offset, sb_bindex; | |
44 | ||
f3bc08c5 MD |
45 | /* |
46 | * Verify that faults are only done on the range of pages owned by the | |
47 | * reader. | |
48 | */ | |
49 | offset = pgoff << PAGE_SHIFT; | |
50 | sb_bindex = subbuffer_id_get_index(config, buf->backend.buf_rsb.id); | |
51 | if (!(offset >= buf->backend.array[sb_bindex]->mmap_offset | |
52 | && offset < buf->backend.array[sb_bindex]->mmap_offset + | |
53 | buf->backend.chan->backend.subbuf_size)) | |
54 | return VM_FAULT_SIGBUS; | |
55 | /* | |
0112cb7b MD |
56 | * ring_buffer_read_get_pfn() gets the page frame number for the |
57 | * current reader's pages. | |
f3bc08c5 | 58 | */ |
0112cb7b MD |
59 | pfnp = lib_ring_buffer_read_get_pfn(&buf->backend, offset, &virt); |
60 | if (!*pfnp) | |
f3bc08c5 | 61 | return VM_FAULT_SIGBUS; |
0112cb7b MD |
62 | get_page(pfn_to_page(*pfnp)); |
63 | vmf->page = pfn_to_page(*pfnp); | |
f3bc08c5 MD |
64 | |
65 | return 0; | |
66 | } | |
67 | ||
52a391bd FD |
68 | #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,11,0)) |
69 | static int lib_ring_buffer_fault(struct vm_fault *vmf) | |
70 | { | |
71 | struct vm_area_struct *vma = vmf->vma; | |
72 | return lib_ring_buffer_fault_compat(vma, vmf); | |
73 | } | |
74 | #else /* #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,11,0)) */ | |
75 | static int lib_ring_buffer_fault(struct vm_area_struct *vma, struct vm_fault *vmf) | |
76 | { | |
77 | return lib_ring_buffer_fault_compat(vma, vmf); | |
78 | } | |
79 | #endif /* #else #if (LINUX_VERSION_CODE >= KERNEL_VERSION(4,11,0)) */ | |
80 | ||
f3bc08c5 MD |
81 | /* |
82 | * vm_ops for ring buffer file mappings. | |
83 | */ | |
84 | static const struct vm_operations_struct lib_ring_buffer_mmap_ops = { | |
85 | .fault = lib_ring_buffer_fault, | |
86 | }; | |
87 | ||
88 | /** | |
89 | * lib_ring_buffer_mmap_buf: - mmap channel buffer to process address space | |
90 | * @buf: ring buffer to map | |
91 | * @vma: vm_area_struct describing memory to be mapped | |
92 | * | |
93 | * Returns 0 if ok, negative on error | |
94 | * | |
95 | * Caller should already have grabbed mmap_sem. | |
96 | */ | |
97 | static int lib_ring_buffer_mmap_buf(struct lib_ring_buffer *buf, | |
98 | struct vm_area_struct *vma) | |
99 | { | |
100 | unsigned long length = vma->vm_end - vma->vm_start; | |
101 | struct channel *chan = buf->backend.chan; | |
5a8fd222 | 102 | const struct lib_ring_buffer_config *config = &chan->backend.config; |
f3bc08c5 MD |
103 | unsigned long mmap_buf_len; |
104 | ||
105 | if (config->output != RING_BUFFER_MMAP) | |
106 | return -EINVAL; | |
107 | ||
f3bc08c5 MD |
108 | mmap_buf_len = chan->backend.buf_size; |
109 | if (chan->backend.extra_reader_sb) | |
110 | mmap_buf_len += chan->backend.subbuf_size; | |
111 | ||
112 | if (length != mmap_buf_len) | |
113 | return -EINVAL; | |
114 | ||
115 | vma->vm_ops = &lib_ring_buffer_mmap_ops; | |
116 | vma->vm_flags |= VM_DONTEXPAND; | |
117 | vma->vm_private_data = buf; | |
118 | ||
119 | return 0; | |
120 | } | |
121 | ||
d83004aa JD |
122 | int lib_ring_buffer_mmap(struct file *filp, struct vm_area_struct *vma, |
123 | struct lib_ring_buffer *buf) | |
124 | { | |
125 | return lib_ring_buffer_mmap_buf(buf, vma); | |
126 | } | |
127 | EXPORT_SYMBOL_GPL(lib_ring_buffer_mmap); | |
128 | ||
f3bc08c5 | 129 | /** |
d83004aa | 130 | * vfs_lib_ring_buffer_mmap - mmap file op |
f3bc08c5 MD |
131 | * @filp: the file |
132 | * @vma: the vma describing what to map | |
133 | * | |
134 | * Calls upon lib_ring_buffer_mmap_buf() to map the file into user space. | |
135 | */ | |
d83004aa | 136 | int vfs_lib_ring_buffer_mmap(struct file *filp, struct vm_area_struct *vma) |
f3bc08c5 MD |
137 | { |
138 | struct lib_ring_buffer *buf = filp->private_data; | |
d83004aa | 139 | return lib_ring_buffer_mmap(filp, vma, buf); |
f3bc08c5 | 140 | } |
d83004aa | 141 | EXPORT_SYMBOL_GPL(vfs_lib_ring_buffer_mmap); |